RobzWorkz #8d: Improving the 328 Fuel System and Peripheral Hoses (Remaining Hoses)

Greetings FChatters!!!

This is the 4th installment of by 328 fuel system rebuild. This thread will deal with the installation of the remaining peripheral hoses, minus the two long hoses for air injection and blow-by which go under the intake plenum; both are deferred until I have reinstalled the intake.

The systems concerned are: air injection; blow-by; auxiliary air, and; brake booster vacuum line. All hoses herein, save for the small 3/16" vacuum lines for the air injection electrovalve and for the ignition ECU were purchased from Aeroquip. Diagrams for these systems are reproduced below.

As before, please reference the earlier RobzWorkz #8 threads for precautions and safety/preparation issues. Use discretion regarding the need to jack up the car for installation of hoses; my experience is that jacking and removing wheels and wheel well liners are requisite for installing these hoses. It is possible to replace the aux air and air injection hoses without jacking the car, but added difficulty will be present since access via the left wheel well is beneficial for the process.

There will be a post for each of the systems involved.
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Replacing the air injection hoses should be coupled with cleaning and testing the air injection electrovalve-controlled valve (uses vacuum sense to activate; to test, I installed a vacuum line on the top and sucked air to change state and poured water through it; sorry, I have no pics of this, but it worked fine). Also, it is a good idea to check that the electrovalve itself is not open or shorted; my resistence check thereof resulted in 44 Ohms detected. I did no other checks on this system.

The operation of the air injection system is explained in the 328 Owner's Manual around pp 71-72 (ref the 1989 manual...should be similar to 1986-88 models). Two electronic sensors, oil temp and coolant temp, are used to activate the electrovalve for injection activation by intake vacuum. The coolant temp sensor is installed in the coolant expansion tank; the oil temp sensor is installed at the forward bottom of the engine sump where the lower blow-by hose connects to the sump. It's a good idea to clean the contacts on the sensors and insulate with dielectric paste (dielectric paste commonly used for ignition wires). Testing and troubleshooting are beyond the scope of this hose replacement effort. It is welcomed for anyone to inform us of a testing procedure. The most common issues with the air injection system are electronic failures, check valve leaks (drivability and idle problems) and engine block leaks (chatter noise). Often, the system is entirely removed and plugs are installed on the block at the exhaust ports (plugs for the 328 are available from Verrell at Unobtainium).

The pics below show my new hoses. As can be seen, I used hose lengths that were assymetric, vice symmetric OEM, so I could locate the long hose going under the intake plenum better. If my system works correctly, since there are check valves in the exhaust portions, no issues should be presented from the assymmetry (no interesting/unexpected exhaust phase modes). If I do need to change back to symmetric, I will post as such.
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The blow-by system is self-activated; no sensors engage anything therein. This system is basically the same as the common "Crankcase Ventillation System" in legacy automobiles. The most complicated item is the oil vapor separator. The basic idea is to allow engine vapors (usually combustables) in the oil system to be ventillated into the intake and consumed by the engine, thus minimizing emissions. Unlike newer engine systems, there is no PCV valve present; pressure variation is accommodated with the oil/vapor separator.

For some, the oil/vapor separator, when removed and checked out, was a rusty mess, requiring immediate replacement. Rust pits and holes can be present. This is why I recommend removing, stripping, cleaning out (with carb cleaner) and repainting the separator, simply as an inspection precaution to indicate a need for replacement. My separator (being "younger" than most) was in acceptable condition and simply needed cleaning out and a repaint. Replacements do seem readily available in the market.

The pics show my system with my new hoses.

As part of my effort, since my original valve cover crossover pipe was a bit mangled, I ordered a new one from Eurospares. The new pipe was acceptable for the system, but I felt that it was weakly constructed and chose to reinforce it with QuickSteel at the center joint; afterwards, a new coat of aluminum-colored paint after primer was applied. Also, I found that the pipe diameters for the short lines going to the valve covers were too narrow; to fix, I applied RTV black with some bycycle inner tube rubber wrapped around as a gap filler...enough to install the hose sections with a good fit. The clamps cemented the system in place well.

There is one hose thet connects the rear valve cover/head to the block. It's not that easy to get to, so take your time and use the wheel well access to suit. Also, since this hose was very close in proximity to the exhaust temperature, I felt it worthy to fabricate a heat shield to protect the hose and the electrical cables in that area. I felt that the heat in this area may contribute to premature hose hardening (the hose I removed was quite hardened, but stll somewhat pliable, but not as much as the other hoses). I made the heat shield curved away from the hose area as much as practical to scatter the heat. To assiste with shield installation, I used CA glue to attach to the hose housing. Also, I fabricated a gasket from commonly-available gasket material and used black RTV to seal. For the hard-to-reach flanges, I uses a flat blade screwdriver to apply the RTV.

The last pic shows the installed crossover after installing other hoses as well.
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Can't help you with that one, Conan. I checked the Rutlands diagrams: the electrovalves are different part #'s. The best thing to do is review the owner's manuals for both the US and CH version and see if the electrovalve settings are the same. Also, from reviewing your other systems, your car has a different aux air system than the US version. Since all these systems are involved together in emissions controls and are "tuned" for their specific country's laws, I would avoid cross-parting the systems. That "bomb" may have been a (last minute design) part required for dampening air fluctuations in the CH version after all the other stuff was done (the "bomb" is called an expansion tank). Thus, I would think, to remove it would entail replacement of all emissions systems as US. This would be very annoying.

If your "bomb" is broken, I would simply remove the air injection altogether if your state permits it. Install Verrell's plugs and keep the removed system available in storage for the next owner.

Good Luck!

 

(Please forgive my misspelled Blow-by system title.)

The Auxiliary air system is presented in two posts: one for the air-flow sensor, and the other for the aux air lines and valve.

The aux air system is used in combination with the air sensor to facilitate fast start up idle speed. The aux air valve is designed to add a cross-sectional area increase in the idle air flow line size during start-up when cool (the valve has a bi-metal strip with a connector to activate control heat as necessary, along with the heat from the coolant expansion tank). The valve is designed to close as engine heat rises. Thus allowed is a faster start up idle speed.

The general (warmed) idle air path is combined there, and is parallel to the aux air line; both are combined and allowed to the intake via lines underneath the intake plenum into each cylinder riser (this line is also used to admit fuel from the cold start injector). The warmed idle is the adjustable with a spring loaded pointed bolt located on the air sensor body.

For this effort, improving the air-flow sensor consisted of cleaning and inspecting only. Since I had good engine performance, I did not dismantle the sensor mechanics. I only cleaned it and lubricated it with a small bit of oil. I also did not adjust any screws, etc. for the sensor plate lever and settings. Also, I did a (very fine and soft and delicate, 1500grit minimum) sanding on the plate as well since it had minor surface corrosion; this was only to mitigate much of the corrosion; I applied a little oil little to minimize more corrosion. Avoid hard manipulation/sanding on the plate...it is essential to the sensor's operation.

I did fully remove the idle adjuster from the body to facilitate cleaning. When re-installing, just install with a couple of turns to keep in place. Proper adjustment requires a warm running engine.

I also replaced the sensor body gasket.

Pics below show the process.

For the cleaning, I used acetone. On the rough (cast) surfaces, I used a Dremel wire wheel.
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This part included a simple test of the aux air valve and installation of hoses. Not included are the parts under the intake plenum; these are deferred until after the CIS rebuild and the intake is refurbished.

Within this system, there is a hose elbow downstream the aux air valve. I chose to omit this due to its excessive cost and legacy materials. FYI, there is another, identical, elbow used for the cold start injector. I have yet to decide to remove it since it is a confined area and thus not easily omitted.

Checking the aux air valve included a resistance check to verify that there was no open or short and a heating check to verify that the aperture reduced in size. I used a hobby heat gun for the (only mild) heat check.

Note: there has been a lot of discussion in a recent thread about the aux air valve. In this effort, I chose not to conduct a full cycle test (open to close) since there was no Bosch-derived description of the process. Some have claimed that applying 12VDC to the terminals would close the aperture and show proper operation; others recommended placing in an oven. I believe neither is sufficient nor permissible for conducting a solid test for two reasons: 1) the temperatures are not exact to published specs, and 2) applying a full 12VDC may introduce too much current, causing premature failure. It is known that the aux air line is supposed to gradually close its aperture as the engine warms up, thus indicating an ECU-applied control current with an environmental thermal input. Thus my simple resistance check and heat-aperture reduction check should be well-within expected operational boundaries. Also of concern was the high cost of the Ferrari valve, especially when compared to other available systems: this is likely due to the special shape of the internal aperture admitted in the valve (several designs for several vehicles), and the expected thermal heat presented from the coolant expansion tank. I would also assert that almost any aux air valve designed for an 8-cylinder car would be sufficient for the application, thus reduced cost would be available for this application. Thus is relegated a complete testing effort herein.

Interestingly, as a reminder to the simplicity of the aux air valve as a system component, it can be bypassed altogether and the idle manually manipulated during engine startup (all that is needed is to first set correct idle when warmed). To do this, one would block the line upstram of the aux air valve altogether (a round chunk of rubber would work without destroying the aux air valve); when starting, first open the (correctly set) idle a known number of turns (from experience); as the engine heats up, reduce the idle sequentially so as to arrive at the warm nominal idle. Just use a glove and don't get burned. You would then become an emissions component .

The pics below show my test and installation, beginning with the diagram.
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The final installment for this thread is the replacement of the brake vacuum line.
This line, like the long coolant hose that lies with it, snakes from the rear engine bay, along the lower left channel (below the left hand door) and into the wheel well area up front.

The brake line includes a check valve to maintain vacuum in the brake reservior, likely to allow continued power braking in case of engine stop. The valve does have a direction indicator, so be sure to install it in the correct direction.

Replacing this hose without removing the left gas tank requires using a "messenger" approach with the old hose connected to the new. The old hose is attached to the new and "fished-through" the path by push/pull methods.

My effort with the cooling line can be seen in my RobzWorkz #7: I was able to route the new coolant hose from back to front successfully. However, for the brake line, my success was achieved going from front to back. This could be the fact that I used the brake line check valve as a connector between the old and new hoses (the coolant connector was of shorter length than the brake line check valve). It was a success although requiring persistence. However, if ever removing the gas tanks from the car entirely, this would be an excellent time to replace both the brake vacuum and coolant hoses together at once; this will limit push/pull strees applied using the messenger techniques (same goes for replacing the AC lines on the right side).

The 7th picture below shows the messenger attachment comprising old and new hoses connected with the chack valve. The setup here would be for "back-to-front" messenger; recall, I had better success with the "front-to-back" version, so the pic is essentially showing the reverse of my successful effort.

Pics are also given which shows my use of spare coolant hose and zip-ties to mount the hoses in place after installation. Use spare hose to prevent chafing.

The final 2 pics are of the pertinent diagrams.

See pics below.

All done with RobzWorkz #8d...enjoy.
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Thanks, Andy!

Your
AAV assessment sounds plausable. Will you please do the experiment at your risk and let us know? Even though it's 12VDC, how long until the turn off...it's likely a temperature thing, right? My assumption is that as long as 12VDC is present, the heater element is heating, regardless of the position of the strip. There is likely a tripper in the circuit for stopping the current....just my guess.

STEVE???

BTW, I love doin' the threads...self-actualization and all.

 

So what happens when the engine is hot enough on its own? What causes the 12VDC to turn off and stop heating the AAV and wearing out the heater resistor? Wouldn't it be some thermal input? Or, is the resistance, as it increases, high enough to reduce current low enough to effectively turn the AAV off (self-elimination)? I knew this was going to become a bigger issue than expected.

So, is my simple test enough to allow continued use of the AAV? That's the pertinent question here, right? I still believe it is.

 

Excellent Andy and Steve! I believe in peer-review for these efforts.

So, doing a 12VDC test to check closed the AAV would be a good option then.

BTW, WUR coming soon enough.

 

Hello FChatters!

I have completed my fuel system refurb and testing (more threads coming)! When I finished and wanted to start the engine, I noticed that the FP didn't turn on properly.

Symptom: the engine started and 3-4 seconds later, cut off. In order to run continuously, I had to remove the FP safety switch connection! (FYI, the engine run was satisfactory)

The culprit was a shorted safety switch.

I realized that I made an error in understanding the FP safety switch operation: my earlier assumption was that the connector was a simple short and was there to route a signal somehow to the FP to let the circuit know the engine was running...I even checked it this way (I verified the short) as satisfactory (NOT!). Even Probst wrote that the safety circuit was often signal-based (such as a tach signal going to a FP control circuit, and would need bridging to deactivate); he also mentioned the "old school" method of sensing the air flow sensor position.

More investigation required...

It turns out the 328 FP safety switch is the "old school" kind, whereby the sensor plate arm completes the FP circuit when the plate is in zero position (no air flow) and shuts off the FP. Thus my assumption that a short was always present meant my FP was always going to turn off...BAD.

To fix, I did some investigating and found Paul308's drawing of the curcuit. I owe him many thanks for this one since the circuits as shown in the electronic diagrams are hard to trace WRT operation. Pic 1 is his FC-published drawing.

I thus decided that, after all my work to get things replaced, removal of the air sensor was necessary to fix the FP safety switch. I thus devised a method for air sensor removal while keeping the fuel distributor mechanically/hydrostatically connected. I also found that disassembly of the safety switch was necessary in order to clean, mitigate the short, and prevent later shorts.

The pics below show the operation.
The procedure:
1)remove the flexible intake plenum, AAV/idle air hose lines and air filter housing;
2)remove the 3 long screws attaching the distributor to the sensor;
3)for lambda control systems, remove bolt retaining frequency valve;
4)remove sensor mounting nuts (remove the nuts on the outer corners first...not the one next to the shock and next to the rear firewall; this will minimize tilt while removing; to gain access to the inner most rear nut, I had to lift the distributor out and position out of the way and use a socket with a long extension);
5)lift the CIS distributor and lines as a whole and lift out the sensor from underneath;
6)support the sensor to minimize stress on the flexible fuel lines; I used towels and a piece of hose);
7)disassemble the air sensor and the safety switch, clean all parts, verify insulators present, test the switch operation by placing the sensor vane arm in contact with the switch contact and checking the shore associated with a sensor on zero position; use a multi meter here;
8)reassemble sensor, check switch operation again, and reassemble all as a reverse operation. It's a good idea to replace the sensor housing gasket. When assembling the sensor housing, be sure to check for free vane movement during the assembly (vane travel can be affected depending on the torquing process used; torque value not known, so I decided on about 8ft-lb).

All done and the engine started normally with proper FP safety switch operation verified.

The last two pics show the final hose assembly with hoses going into the filter housing...all prior to reinstalling the wheel well. Top view shown as well.
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